Ace Inhibitors (Includes Fosinopril/hydrochlorothiazide) ↔ Angioedema

Severe Potential Hazard, Moderate plausibility

Applies to: Angioedema

Patients with a history of angioedema unrelated to ACE inhibitors may be at increased risk of angioedema while receiving an ACE inhibitor. Patients should be advised to immediately report any signs or symptoms suggestive of angioedema (swelling of face, extremities, eyes, lips, or tongue, or difficulty swallowing or breathing) and to stop taking the medication until otherwise directed by their physician. Emergency therapy and/or measures to prevent airway obstruction are required for angioedema involving the tongue, glottis, or larynx. The use of these agents is contraindicated in patients with hereditary angioedema or a history of idiopathic angioedema. Treatment with ACE inhibitors should be discontinued permanently if angioedema develops in association with therapy.

ACE inhibitors may cause bone marrow suppression, rarely in uncomplicated individuals but more frequently in patients with renal impairment, especially if they also have a collagen-vascular disease such as systemic lupus erythematosus or scleroderma. Neutropenia, agranulocytosis, aplastic anemia, hemolytic anemia, eosinophilia and thrombocytopenia have been reported, mostly with captopril. Therapy with ACE inhibitors should be administered cautiously in patients with preexisting blood dyscrasias or complications that may increase the risk of bone marrow depression during ACE inhibitor therapy. Monitoring of blood counts, particularly white blood cells, should be considered.

Ace Inhibitors (Includes Fosinopril/hydrochlorothiazide) ↔ Chf

Severe Potential Hazard, Moderate plausibility

Applies to: Congestive Heart Failure

ACE inhibitors can cause marked renal impairment in patients whose renal function depends on the activity of the renin-angiotensin-aldosterone system. In addition, symptomatic and sometimes excessive hypotension can occur in susceptible individuals, particularly during the initiation of treatment, which may compromise renal and myocardial perfusion. In patients with severe congestive heart failure (CHF), treatment with ACE inhibitors may be associated with oliguria and/or progressive azotemia and, rarely, renal failure, myocardial ischemia and death. Therapy with ACE inhibitors should be initiated under very close medical supervision in patients with severe CHF, especially when accompanied by volume and/or sodium depletion. Patients should be monitored closely for several hours after an initial dose until blood pressure has stabilized, and followed closely for the first 2 weeks of treatment and whenever the dosage of ACE inhibitor or diuretic is increased. If feasible, the risk of severe hypotension may be minimized by reducing or temporarily withholding the dosing of diuretics and/or liberalizing dietary sodium intake for 2 to 3 days prior to starting ACE inhibitor therapy. In patients who experience a worsening of renal function, discontinuation of ACE inhibitor therapy is usually not required provided there is symptomatic improvement of the heart failure and renal deterioration is well-tolerated. Transient hypotension is also not a contraindication to further treatment with ACE inhibitors. After blood pressure stabilizes, therapy can usually be reinstated with caution, although a lower dosage of the ACE inhibitor and/or dosage reduction or discontinuation of concomitantly administered diuretics may be necessary.

Anaphylactoid reactions have been reported in patients undergoing hemodialysis with high-flux polyacrylonitrile membranes and treated concomitantly with an ACE inhibitor. The frequency and mechanism of this interaction have not been established, and it is not known whether the interaction occurs with other membrane types. Therapy with ACE inhibitors should be administered cautiously in patients requiring hemodialysis.

In patients with hyperkalemia, especially those associated with impaired renal function or congestive heart failure, ACE inhibitors may further raise serum potassium levels. Therapy with ACE inhibitors should be administered cautiously in patients with or predisposed to hyperkalemia, and serum potassium levels should be carefully monitored. Risk factors for the development of hyperkalemia during ACE inhibitor therapy include renal insufficiency, diabetes mellitus, and the concomitant use of potassium-sparing diuretics, potassium supplements, and/or potassium-containing salt substitutes.

ACE inhibitors can cause symptomatic hypotension, most often during the initiation of therapy and in patients who are volume- and/or sodium-depleted or treated for congestive heart failure (CHF). Therapy with ACE inhibitors should be administered cautiously in such patients and in those predisposed to hypovolemic or hyponatremic states (e.g., patients on diuretic therapy, especially if it was recently instituted; those on dietary salt restriction; those with severe or prolonged diarrhea or vomiting; and renal dialysis patients). Volume and/or sodium depletion should be corrected prior to initiating therapy with ACE inhibitors, and the patient should be hemodynamically stable. If concomitant diuretics and/or dietary sodium restriction are employed, reducing or temporarily withholding the dosing of diuretics and/or liberalizing dietary sodium intake for 2 to 3 days in advance can help minimize the risk of severe hypotension in patients who are able to tolerate such adjustments. ACE inhibitors should also be used cautiously in patients in whom excessive hypotension may have serious consequences, such as patients with coronary or cerebrovascular insufficiency. Patients at risk for excessive hypotension should initiate ACE inhibitor therapy under very close medical supervision, and followed closely for the first 2 weeks of treatment and whenever the dosage of ACE inhibitor or diuretic is increased.

The use of thiazide diuretics is commonly associated with loss of electrolytes, most significantly potassium but also sodium, chloride, bicarbonate, and magnesium. The loss of other electrolytes such as phosphate, bromide and iodide is usually slight. Potassium and magnesium depletion may lead to cardiac arrhythmias and cardiac arrest. Other electrolyte-related complications include metabolic alkalosis and hyponatremia, which are rarely life-threatening. Therapy with thiazide diuretics should be administered cautiously in patients with or predisposed to fluid and electrolyte depletion, including patients with primary or secondary aldosteronism (may have low potassium levels); those with severe or prolonged diarrhea or vomiting; and those with poor nutritional status. Fluid and electrolyte abnormalities should be corrected prior to initiating therapy, and blood pressure as well as serum electrolyte concentrations monitored periodically and maintained at normal ranges during therapy. Patients should be advised to immediately report signs and symptoms of fluid or electrolyte imbalance, including dry mouth, thirst, weakness, lethargy, drowsiness, restlessness, muscle pains or cramps, muscular fatigue, hypotension, oliguria, tachycardia, arrhythmia, or gastrointestinal disturbances such as nausea and vomiting. Digitalized patients and patients with a history of ventricular arrhythmias should be monitored carefully, since development of hypokalemia may be particularly dangerous in these patients. The risk of hypokalemia may be minimized by slow diuresis, a lower thiazide dosage, potassium supplementation, or combined use with a potassium-sparing diuretic.

Thiazides (Includes Fosinopril/hydrochlorothiazide) ↔ Liver Disease

Severe Potential Hazard, High plausibility

Applies to: Liver Disease

Patients with severe liver disease or cirrhosis are very susceptible to thiazide-induced hypokalemic hypochloremic alkalosis. Blood ammonia concentrations may be further increased in patients with previously elevated concentrations. Hepatic encephalopathy and death have occurred secondary to the electrolyte alterations accompanying diuretic use. Therapy with thiazide diuretics should be administered cautiously in patients with impaired hepatic function or progressive liver disease, and discontinued promptly if signs of impending hepatic coma appear (e.g., tremors, confusion, and increased jaundice).

The use of thiazide diuretics has been reported to possibly exacerbate or activate systemic lupus erythematosus. Reported cases have generally been associated with chlorothiazide and hydrochlorothiazide. Therapy with thiazide diuretics should be administered cautiously in patients with a history or risk of SLE.

Thiazide diuretics may be ineffective when the glomerular filtration rate is low (GFR < 25 mL/min) because they are not expected to be filtered into the renal tubule, their site of action. In addition, thiazide diuretics decrease the GFR and may precipitate azotemia in renal disease. Cumulative effects may also develop because most of these drugs are excreted unchanged in the urine by glomerular filtration and active tubular secretion. Therapy with thiazide diuretics should be administered cautiously at reduced dosages in patients with renal impairment. If renal function becomes progressively worse, as indicated by rising BUN or serum creatinine levels, an interruption or discontinuation of thiazide therapy should be considered.

With the exception of fosinopril, ACE inhibitors (and/or their active metabolites in some cases) are primarily eliminated by the kidney and may accumulate in patients with renal impairment. ACE inhibitors can also worsen renal function in some patients by blocking the effect of angiotensin II-mediated efferent arteriolar vasoconstriction, thereby decreasing glomerular filtration. Therapy with ACE inhibitors should be administered cautiously in patients with preexisting renal dysfunction, particularly those with renovascular disease. Patients with moderate to severe renal impairment usually require lower or less frequent doses and smaller increments in dose. In addition, a dosage reduction or discontinuation of any concomitantly administered diuretics may be helpful. Fosinopril probably does not require dosage adjustments unless hepatic function is also significantly impaired.

In patients with bilateral renal artery stenosis or renal artery stenosis in a solitary kidney, ACE inhibitors may reduce renal perfusion to a critically low level. Renal function should be monitored closely for the first few weeks of therapy.

Fosinopril is primarily metabolized by hepatic and gut wall esterases to its active moiety, fosinoprilat, patients with impaired liver function could develop elevated plasma levels of unchanged fosinopril. In a study in patients with alcoholic or biliary cirrhosis, the extent of hydrolysis was unaffected, although the rate was slowed. In these patients, the apparent total body clearance of fosinoprilat was decreased and the plasma AUC approximately doubled.

Moderate

Thiazides (Includes Fosinopril/hydrochlorothiazide) ↔ Asthma

Moderate Potential Hazard, Moderate plausibility

Applies to: Asthma

Thiazide diuretics should be used with caution in patients with history of bronchial asthma as sensitivity reactions may occur.

Moderate

Thiazides (Includes Fosinopril/hydrochlorothiazide) ↔ Diabetes

Moderate Potential Hazard, Moderate plausibility

Applies to: Diabetes Mellitus, Abnormal Glucose Tolerance

Thiazide diuretics may cause hyperglycemia and glycosuria in patients with diabetes. They may also precipitate diabetes in prediabetic patients. These effects are usually reversible following discontinuation of the drugs. Therapy with thiazide diuretics should be administered cautiously in patients with diabetes mellitus, glucose intolerance, or a predisposition to hyperglycemia. Patients with diabetes mellitus should be monitored more closely during thiazide therapy, and their antidiabetic regimen adjusted accordingly.

Thiazides (Includes Fosinopril/hydrochlorothiazide) ↔ Hyperlipidemia

Moderate Potential Hazard, Moderate plausibility

Applies to: Hyperlipidemia

Thiazide diuretics may increase serum triglyceride and cholesterol levels, primarily LDL and VLDL. Whether these effects are dose-related and sustained during chronic therapy are unknown. Patients with preexisting hyperlipidemia may require closer monitoring during thiazide therapy, and adjustments made accordingly in their lipid-lowering regimen

Urinary calcium excretion is decreased by thiazide diuretics during chronic administration. Pathologic changes in the parathyroid gland with hypercalcemia and hypophosphatemia have been reported during prolonged therapy. However, the common complications of hyperparathyroidism such as renal lithiasis, bone resorption, and peptic ulceration have not been seen. Clinicians should be cognizant of these effects when prescribing or administering thiazide therapy to patients with hyperparathyroidism. These drugs should be discontinued before carrying out tests for parathyroid function.

Thiazides (Includes Fosinopril/hydrochlorothiazide) ↔ Hyperuricemia

Moderate Potential Hazard, High plausibility

Applies to: Gout

Thiazide diuretics decrease the rate of uric acid excretion. Hyperuricemia occurs frequently but is usually asymptomatic and rarely leads to clinical gout except in patients with a history of gout or chronic renal failure. Therapy with thiazide diuretics should be administered cautiously in such patients.

Thiazide diuretics may decrease serum PBI (protein-bound iodine) levels without associated thyroid disturbance. Clinicians should be cognizant of this effect when prescribing or administering thiazide therapy to patients with thyroid disorders.